Detergent compositions having improved foam-stability



United States PatentO Delaware No Drawing. Filed Jan. 8, 1957, Ser. No.632,967 3 Claims. (Cl. 252-161) The present invention relates to themanufacture of detergent compositions. The invention likewise relates todetergent compositions exhibiting improved foam-stability. Other objectsand advantages of the invention will appear hereinafter.

In accordance with the present invention an improvement in thefoam-stability characteristics of alkyl aryl sulfonate detergents hasbeen discovered in compositions containing the said sulfonates incombination with hydrolyzed polyacrylonitrile.

The sulfonate component of the present invention is an alkaline saltsuch as an amine salt, potassium, ammonium or sodium salt of thesulfonate of an alkylated aromatic hydrocarbon which may be prepared bycondensing an aliphatic hydrocarbon having from 5 to 18 carbon atomswith an aromatic hydrocarbon selected from the class consisting ofbenzene, toluene and xylene, and thereafter sulfonating the product andneutralizing it with an alkaline material. The preferred aromatichydrocarbon which is alkylated of this group is usually benzene, but thecompounds obtained from toluene and xylene have also been found to havedesirable properties as detergent compositions. The alkyl group may havefrom 5 to 18 carbon atoms, preferably about 9 to 18 carbon atoms averagelength, or more preferably 10 to 12 carbon atoms average chain length,such as may be obtained from olefin polymers or from kerosene. A typicalcomposition of this type is produced by alkylating the aromatichydrocarbon with an olefin hydrocarbon averaging 5 to 18 carbon atoms inthe molecule, and thereafter sulfonating and neutralizing the product.

It has been found that detergent agents based solely upon the alkalinesalts of alkyl aryl sulfonates have only moderately effectivefoam-stability, particularly in the presence of greases, soiled clothingor dishes. It is ob viously desirable to maintain a stable foam indetergents since the efiiciency of the detergents is often judged by thefoam characteristics thereof.

The second component of the present composition is hydrolyzedpolyacrylonitrile, such as is obtained by the acid or alkali catalyzedhydrolysis of polyacrylonitrile, as described in US. Patents 2,625,529and 2,727,835. The polyacrylonitrile may be of either a high or lowmolecular weight and the hydrolyzed product may have a wide range ofviscosities as employed in the present invention.

Examples will now be given illustrating preferred embodiments of theinvention, but it will be understood that the present invention is notto be limited by the details thereof. Parts are by weight unlessotherwise indicated.

A mixture was prepared from 99% by weight of the sodium salt of dodecylbenzenesulfonic acid, together with 1% by weight of hydrolyzedpolyacrylonitrile (viscosity 0.17 poises at 1% concentration). Thismixture was dissolved in water to give a series of solutions of variousconcentrations. The foam-stability of each of "ice these samples wasdetermined by the method set forth below and the following resultsobtained.

Concentration: Percent foam-stability at 180 min.

surface-active components is dissolved in distilled water.

The solution is then transferred to a 500 ml. volumetric flask anddiluted to approximately 150-200 ml. with dis-' Two hundred and fiftyml. of hard water tilled water. of 600 ppm hardness is then added to thesolution, which is then brought to the mark with distilled water'toprovide a final test solution of 300 p.p.m. hardness.

In carrying out the foam-stability test, 50 ml. of the above-describedtest solution is first used to rinse the Walls of the 1000 ml. graduateused as the test vessel. A foam pipette is then filled with the abovetest solution to the 200 ml. mark. The pipette is immediately clamped inposition with the outlet centered cm. above the 50 ml. mark on thegraduate, after which the stopcock is opened. The 200 ml. of solution isrun from the pipette into the 1000 ml. graduated cylinder, and thevolume of the liquid level is noted, together with the time. Afterobtaining the value for the liquid volume, the graduate is set to oneside and covered with a petri dish cover, thus preventing particles offoreign matter from dropping into the foam. The total volume in thecylinder (foam plus liquid) is read and the initial foam volume is thencalculated as:

Total volume-liquid volume=foam volume Total volume readings are thentaken at 120, and minutes after initial foam formation and the foamvolumes calculated. The calculation of the foam-stability is carried outin accordance with the following formula:

Foam volume at 180 minutes Initial foam volume The compositions of thepresent invention are of particular utility in detergent compositions inwhich a stable foam is desirable such as in household dishwashingcompositions and in other household and commercial detergents whenfoam-stability is required. For general washing purposes the compositionis employed in concentrations varying from 0.075% to 10% by weight ofhydrolyzed polyacrylonitrile stabilizer relative to the sulfonatecomponent. The composition may be produced as a dry mixture of the twocomponents but it is also contemplated that other detergents, dyes,builders, fillers, etc. may be mixed with or employed together with theabove composition.

When used as a detergent the herein-disclosed compositions may beemployed either in the 100% active form of the sulfonate with thestabilizer, or they may be combined with alkali metal builder salts suchas alkali metal phosphates, sulfates, carbonates, silicates, or withcarbohydrate materials such as starch, carboxymethylcellulose, etc. ormixtures of these materials. When employed with X 100: foam stabilitybuildefsalts-the combination of the activecomponents are utilized inamount varying from 10% to 50% or more by weight of active material inthe built composition. Suitable alkali metal salts utilizable in thesecompositions are the disodium orthophosphate, trisodium orthophosphate,tetrasodium pyrophosphate, sodium metaphosphate, sodiumtripolyphosphate, sodium carbonate, sodium bicarbonate, sodiumsesquicarbonate, sodium silicate, sodium sulfate, etc.

The compositions of the present invention may also be marketedand,utilized as solutions such as aqueous or ethanol solutions; slurriesor pastes of suitable'concentration which maybe used directly or may bediluted at' the time of appl'ication. For example, a paste concentratefor use in a dishwashing composition may be provided from thefollowing components given asWveight percent:

Percent Sbdium sulfonate of dodecyl benzene; (technical gifadecontaining 20%sodium"sulfate")' 76 Hydrolyzed polyacrylonitril'e 9 Water1 5 The-present invention -isnot'to be considered to be Iimited -byr anyof the examples described herein which areigiven by 'w'ay 'ofillustration only; but isto belimited solely bythe scope of the appendedclaims.

What isclaimed is: I 1. A, foam-stable detergent composition consistinges' sentially of thecombination" cha -mixture of from 90% i to"'99.925b'yweight of a'compoundof the' groupcon sisting of the sodium alkylbenzene, alkyl toluene, and alkyl xylene sulfonates, wherein the alkylgroup has from 5 to 18 carbon atoms, and from 0.075% to 10% ofhydrolyzed polyacrylonitrile.

2. A foam-stable detergent composition consisting essentially of thecombination of a mixture consisting of from to 99.925% of a sodium alkylbenzene sulfonate, wherein the alkyl group has from 5 to 18 carbon atomsand from 0.075% to l0% of hydrolyzed polyacrylonitrile.

3. A foam-stable detergent composition consisting essentially of i thecombinationoff'a mixtureconsisting of from 90% to' 99.9 2 -5% ofisodiumdodecyl b'enzene sulfonatea'nd from 0.075% to10%ofhydrolyzed poly--acrylonitrile.

References Cited-in the fileof this patent UNITEDsTAT' Es PATENTS OTHERREF ERENCES Surface 'A'ctive Agents," by 'Schwartz'and Perry, 1949',

Intersien'ce"Publishers, Incl, N.YiC.,.New York, pages 235, 379, 380.

1. A FOAM-STABLE DETERGENT COMPOSITION CONTAINING ESSENTIALLY OF THECOMBINATION OF A MIXTURE OF FROM 90% TO 99.925% BY WEIGHT OF A COMPOUNDOF THE GROUP CONSISTING OF THE SODIUM ALKYL BENZENE, ALKYL TOLUENE, ANDALKYL XYLENE SULFONATES, WHEREIN THE ALKYL GROUP HAS FROM 5 TO 18 CARBONATOMS, AND FROM 0.075% TO 10% OF HYDROLYZED POLYACRYLONITRILE.